Adjustable radiocoils



N. MEDVED ADJUSTABLE RADIOCOILS Feb. s, 1929. 1,701,330

Filed Nov. 20, 1926 2 Sheets-Sheet 1 Feb.5, 1929. f 1,701,330

' N. MEDVED ADJUSTABLE RADIOCOILS /V/Wedvea PATENT OFFICE.

NICHOLAS MEDVERIOF CANTON, OHIO.

ADJUSTABLE RADIOCOILS.

Appuaamn med November 2o, 192s. serial Nc. 149,736.

The invention relates to coils for use in electrical circuits, and more particularly in radio circuits, in various arrangements such as for radio frequency transformers, and includes improvements in the radio coils set forth' in my prior application for patent filed April 6, 1926, Serial No. 100,093; and the objects of the improvements are to provide a more convenient and economical construction and arrangement for the coils of my aforesaid prior application, and to provide, as for use in circuits including a plurality of radio frequency vacuum tubes, a plurality of sets of my improved radio coils arranged for use as for radio frequency transformers in connection with said tubes, there being independent means .associated with each set of adjustable coils whereby the several sets may be independently adjusted and the several circuits may be thereby adjusted or balanced with each other, and means for simultaneously adjusting as for tuning purposes the plurality of balanced transformers.

A further object of the invention is to provide a modilded form of my improved radio coils set forth in my aforesaid prior application.. l

The foregoing and ancillary objects are attained inthe present invention by constructions and arrangements hereinafter described in detail, and illustrated in the accompanying drawings forming part hereof, in which- Figure 1 is a side elevation with portions in axial vertical cross section of a single set of my improved adjustable radio coils,

;as arranged for use as an adjustable radio vbearing brackets 2a and 2b, at the upper ends of which are secured the ends of the longi' tudinally extending parallel upper and lower coil support bearing and slide rods 3 and 3 which may likewise be made of hard rubber. The ends of the rods 3 and 3 preferably tit in suitable apertures 4 in the upper ends of the bearing brackets 2 and 2b, and the ends of the rods may be secured in their bearing apertures in the brackets as by pins 5.

Between the bearing brackets, the rods 3 and 3 pass through suitable apertures 6 in the smaller base wall 7 of one preferably conical frustrum coil support 8, and through suitable sliding apertures 6b in the smaller base wall 7b of another preferably conical frustrum. coil support 8b.

The coil supports 8a and 8b are preferably of identical hollow conical frustrum form, and include the conical Walls 9a and 9b diverging outwardly from the smaller frustrum base walls la and 7b, respectively; and the conical walls 9 and 9" include outer conical surfaces 10a and 10", and inner conical surfaces 11 and 11b, both surfaces being preferably coaxial and having the same taper..

The supports 8u and 8* are preferably coaxially mounted on' the rods 3 and 3 with their larger frustrurn bases adjacent each other as shown, and the smaller base wall 7 of the support 8a preferably having its outer face abutting or closely adjacent the inner face of the bracket 2B, and being secured to the rods 3 andl3 as by the pins 12.

By these means, the support 8a is xed in position upon the rods 3 and 3', and the support 8b is slidable thereon, for varying the longitudinal axial distance between the supports for purposes hereinafter to be eX- plained in detail.

For providing means for very finelyA adjusting the longitudinal distance between the supports 8a and 8, the base wall 7b of the support 8* is provided with a threaded axial aperture 13 in which a rotatable adjusting screw shaft 14 longitudinally llits and extends.

One bearing end 14' of the shaft 14 preferably extends through an Unthreaded loose axial opening 15 in the base 7 of the support 8, and the bearing end 14 of the shaft 14 is preferably supported in a bearing socket 16 in the bracket 2a.

The other bearing end 14 of the screw shaft 14 may beV provided with an outer thrust collar 17 fitting in a suitable bearing aperture 18 in the bracket 2b, and a washer 19 and locking nuts 20 may be provided u on the'shaft for suitably abutting the was er 19 against the inner face of the bracket 2",

whereby the shaft 14 is secured against longitudinal movement, but adapted to be rotated as by means of a knob 21 secured as by a set screw 22 upon the outer extremity of the bearing end 1 as illustrated.

The conical Walls 9a and 9b of the supports 8 and 8b, are preferably made of dielectric material such as hard rubber, and are preferably -provided with openings 23 for reducing the quantity of the dielectric material required for the supports.

The outer surfaces 10El and 10b of the supports carry respectively outer s irally wound. conical coils 24a and 24h, pre erably of the character described in my aforesaid application, Serial No. 100,093; while the surface-11a may support an inner spirally wound conical coil 25a, of a similar character, and another inner spirally wound conical'coil 26a may be spaced from and carried within the coil 25a as by means of a dielectric conical spacer 27.'v

Adjacent terinina1s24af, and 24:1 of the coils 24and 24h may be connected with each other as illustrated to form a split secondary for usin the adjustable coils herein set forth as an adjustable radio frequency transformer.

The outer terminal 25a of the coil 25a and the inner terminal 26a of the coil 26a may vbe connected to each other to form a balancing primary for the split secondary. The other terminals 24a, 241W, 26a and 25a are here shown free, ready to be incorporated inthe aforesaid circuit.

The aforesaid construction and arrangement for my adjustable coilsy is moreeconomical to manufacture andassemble than.

the arrangement disclosed in plication, Serial No. 100,093.

Moreover the coils of the present disclosure may be coaxially aline'd with each other with my prior apgreater accuracy over the whole range of adjustment; and areadapted for a'greater range of adjustment than is possible by the use of the disclosure of my prior application.

The slide rods 3 and 3 accurately maintain l the coaxial arrangement of the coil supports,

`cuits is made ossible.

, The coils w` en used in radio circuits have also been found to have a very small mutual inductance; a given coil may be used sub- 1,7o1,sao

stantially over the whole range of radio broadcasting frequencies; and by reason of the very fine frequency adjustments possible. a greater selectivity in the radio receiving circuit -is obtained.

In addition to the aforesaid advantages of my improved adjustable coils for radio circuits, the adjustable coils may be advantageously used as will be obvious to persons skilled in the art, in other alternatinv or oscillating current circuits, such as telephone circuits or the like, wherever very fine frequency adjustments are desired.

As illustrated in Figs. 2 and 3, a plurality of sets of my improved radio coils may be arranged for use as for a plurality of radio frequency transformers in radio circuits which may include a plurality of radio frequency vacuum tubes, it bein understood that in such circuits a single adjustable radio -frequency transformer is usua 1y associated with each tube, and it is desirable to balance the several tube and transformer circuits with each other; and for tuning purposes it is moreover desirable, after the'sev eral tube and transformer circuits have been balanced with each other, to simultaneously vary the transformer adjustments of the same.

The improved sets of adjustable radio coils arranged for use` as a plurality of radio frequency transformers, illustrated in Figs. 2 and 3, are adapted for the foregoing urposes, and the arrangement includes a ase 101 which may be made of molded dielectric material such as liard\rubber, and provided `with a plurality of upwardly extending end bearing brackets 102t and 102", and intermediate bearing brackets 102c and 1021, at the upper ends of which are secured longitudinally extending parallel upper and lower coil support bearing and slide rods 103 and 103 which may likewise be made of hard rubber. The ends of the rods 103 and 103 preferably fit in suitable apertures 104 in the upper ends the ends'of the rods may be secured in their bearing aperturesin the brackets as by pins 105. l v

Between each of the bearing brackets 102 and 102, 102 and 1021, and 102d and 102", the rods 103 and 103 pass through suitable apertures 106a in the smaller base wall 107a of one referably conical frustrum coil support 10g, and through suitable sliding apertures 106b in the smaller base wall 107b of another preferably conical frustrum coil support 108".

The coil supports 108 and 108b are preferably of identical hollow conical frustrum form, and include the conical walls 109EL and 109b diverging outwardly from the smaller frustrum base walls 107 and 107", and the conical walls 109a and 109b include outer coni; cal surfaces 110a and 110, and inner conical 11o of the bearingbrackets 102'* and 102D, and

.preferably coaxial and having the same ta- The sets of supports 108" and 108" are preferably co'axially mounted on the rods 103 and 108 with the larger frustrum bases of the supports of each set adjacent each other as shown, and the smaller base walls 107" of the supports 108a preferably having their outer base surfaces closely adjacent the opposed surfaces of the brackets 102, 102c and 102".

Means are provided for independently varying the longitudinal distances ofthe supports 108s` from each other, which preferably include stub shafts 112", 112C and 112d journallcd respectively in the upper ends of the brackets 102", 102c and 102, between the rods 103 and 108, and coaxial with the supports 108".

The stub shafts are provided with threaded ends 1121, 112C and 1121 which screw in suitable apertures in the support base walls 107".

Atv the other ends, the stub shafts are pro-` secured against longitudinal thrust, and

whereby rotation of the stub shafts by means of the knobs 112 will vary the longitudinal position of each support 108a with respect to its adjacent bracket, and thereby providing means for independently varying the longitudinal distances of the supports 108ZL from each other.

For providing means for simultaneously an-d very finely adjusting the longitudinal distances between the several supports 108", and the adjacent supports 108, the base walls 107" of the supports 108"`are each provided with a threaded axial aperture 113, through all of which a single rotatable adjusting screw shaft 114 longitudinally fits and eX- tends. The screw shaft 114 also preferably extends through unthreaded loose axial openings 115 in the stub shafts 112 and 112", and one bearing endr114 of the screw shaft 114, is preferably supported in a bearing socket 116 in the stub shaft 112,

The other bearing end 114 of the screw` shaft 114 may be provided with an outer thrust collar 117 fitted in a suitable bearing aperture 118 in the bracket 102", and a Washer 119 and locking nuts 120 may be provided upon the shaft for suitably abutting the washer 19 against the inner face of the bracket 102" whereby the shaft 114 is secured against longitudinal movement, but adapted to be rotated as by means of a knob 121 suit* ably secured upon the outer extremity of the bearing end 114" as illustrated.

The conical walls 109a and 109" of the supports 108" and 108" are preferably made of dielectric material such as hard rubber", and are preferably provided with openings 128 for reducing the quantity of the dielectric material required for tlfe support-s.

The outer surfaces 110a and 110" of each of the supports carry respectively outer spirally wound conical coils 124"L and 124", preferably of the character described in my aforesaid application, Serial No. 100,093; while the surface 111a of each support may sustain an inner spirally wound conical coil 125, of a samilar character.

Adjacent terminals 1243 and 124" of the coils 124a and 124" may be connected with each other as illustrated to form a split secondary, for using each set of the adjustable coils as an adjustable radio frequency trans former.

The terminals 125i" and 125B, of the coils 125", and the terminals '1241" and 124V of the split secondary coils 124a and 124", are illustrated free, ready to be incorporated in several circuits as several radio frequency transformers.

By the aforesaid construction and arrangement for the plurality of sets of my adjustable coils, by independent rotation of the knobs 112", 112c and 112, it is possible to balance the several transformers with respectl to each other; and after the same are balanced, it is possible by rotation of the knob 121 to simultaneously vary the frequencies passed by the balanced transformers.

By these means it is possible insome circuits to dispense entirely with variable condensers for tuning purposes.

I claim:

1. Electrical apparatus including a plurality of spaced brackets, a coil adjacent each bracket, independent adjustablemmeans associated with yeach bracket for selectively adjusting and maintaining the adjacent coil at varying distances from the bracket, a movable coil adjacent each of the first mentioned coils, and means-for varying the distance between each of the first mentioned coils and its adjacent movable coil.

2. Electrical apparatus including a plurality of spaced brackets, a coil adjacent each bracket, independent adjustable means associated with each bracket for selectively adjusting and maintaining the adjacent coil at varying distances from the bracket, a movable coil adjacent each of the first mentionedv coils, and screw means for varying the distance between each of the first mentioned coils and its adjacent movable coil.

3. Electrical apparatus including a plurality of spaced brackets, a vcoil adjacent each bracket, independent adjustable means associated with each bracket for selectively adjusting and maintaining the adjacent coil at varying distances from the bracket, a movciated With each bracketffor selectively adjusting and maintaining the adjacent coil at varying distances from the bracket, a movable coil adjacent each of the first mentioned coils, and screw. means for simultaneously varying the distances between the first mentioned coils and their adjacent movable coils.

5. Electrical apparatus including a plurality of spaced brackets, a coil adjacent each bracket, independent adjustable means associated With each bracket for selectively adjusting and maintaining the adjacent 'coil at varying distances from the bracket, a movable coil adjacent each of the first mentioned coils, and means for simultaneously moving all of the movable coils.

6. Electrical apparatus including a plurality of spaced brackets a coil adjacent each" bracket, independent adjustable means associated with each bracket for selectively adjusting and maintaining the adjacent coil at varying distances from the bracket, a movable coil adjacent each of the first mentioned coils, and screw means for simultaneously n'loving all of' the movable coils.

In testimony that I claim the above, I have hereunto subscribed my name.

NICHOLAS MEDVED. 

